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The genus Triops can be distinguished from the only other genus of Notostraca, Lepidurus, by the form of the telson, which bears a pair of long, thin caudal extensions in Triops, while Lepidurus bears a central platelike process. Only 24 hours after hatching they already resemble miniature versions of the adult form.[1]

Triops eggs enter a state of extended diapause when dry, and will tolerate temperatures of up to 98 °C(208 °F) for 16 hours, whereas the adult cannot survive temperatures above 34 °C(93 °F) for 24 hours or 40 °C(104 °F) for 2 hours.[5] The diapause also prevents the eggs from hatching too soon after rain; the pool must fill with enough water for the dormancy to be broken.[5]

The name Triops comes from the Greekτρία (tría) meaning "three" and ὤψ (ops) meaning "eye".[6] The head of Triops longicaudatus bears a pair of dorsalcompound eyes that lie close to each other and are nearly fused together. The compound eyes are generally sessile (not stalked). In addition, there is a naupliarocellus (the "third eye") between them. The compound eyes are on the surface of the head, but the ocellus is deep within the head. All the eyes, however, are easily visible through the shell covering of the head.

Ludwig Keilhack used the genus name Triops in his 1909 field identification key of the freshwater fauna of Germany. He suggested that the genus name Apus be replaced by Triops Schrank since an avian genus had already been described by Giovanni Antonio Scopoli under the name Apus.[7] However, Robert Gurney preferred the name Apus Schäffer. He suggested that the name '...Triops Schrank, may be returned to the obscurity from which it was unearthed'.[7] This controversy continued and was not resolved until the 1950s.